Hitherto, there have been proposed several examples of a blade shape of a propeller fan for realizing an air blower that achieves reduction in noise level and increase in efficiency. In order to achieve the reduction in noise level of the propeller fan, it is effective to reduce an rpm and necessary to accelerate rise of static pressure. Further, it is also necessary to suppress a turbulence of an air current, to thereby suppress fluctuation of pressure applied to blades.
For example, in Patent Literature 1, there is disclosed a blade including a protruding portion formed on a trailing edge portion of the blade to protrude in a direction reverse to a rotating direction of the blade so that the blade area is increased, thereby increasing a degree of rise of static pressure. Further, in Patent Literature 2, there is disclosed a blade including a recessed portion formed in a region of a leading edge portion close to a boss to be recessed in a rotating direction so that the area covered by an air current passing along the boss side is increased, and further including a protruding portion formed in a region of a trailing edge portion close to the boss to protrude in a direction reverse to the rotating direction.